CVE-2026-34942
Description
Wasmtime is a runtime for WebAssembly. Prior to 24.0.7, 36.0.7, 42.0.2, and 43.0.1, Wasmtime's implementation of transcoding strings into the Component Model's utf16 or latin1+utf16 encodings improperly verified the alignment of reallocated strings. This meant that unaligned pointers could be passed to the host for transcoding which would trigger a host panic. This panic is possible to trigger from malicious guests which transfer very specific strings across components with specific addresses. Host panics are considered a DoS vector in Wasmtime as the panic conditions are controlled by the guest in this situation. This vulnerability is fixed in 24.0.7, 36.0.7, 42.0.2, and 43.0.1.
CVSS Details
CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Threat Intelligence
Weaknesses 1
Affected Products 4
| Vendor | Product | Version | Range |
|---|---|---|---|
| bytecodealliance | wasmtime | * | <24.0.7 |
| bytecodealliance | wasmtime | * | ≥25.0.0 – <36.0.7 |
| bytecodealliance | wasmtime | * | ≥37.0.0 – <42.0.2 |
| bytecodealliance | wasmtime | * | ≥43.0.0 – <43.0.1 |
References 1
- github.com https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-jxhv-7h78-9775
Remediation
No remediation data recorded yet
Check vendor advisories and the NVD entry for patch availability.